Garland MP-GD-10-S - Manual (Page 46)

Part # MPSM07 (03/24/08) Page 46
TESTING & TROUBLESHOOTING
MP-GS-10/20 Troubleshooting Guide
Use this chart with the appropriate wiring diagram, also found in this manual
Mechanical Control
PROBLEM POSSIBLE CAUSE CORRECTIVE ACTION
Fan will not Run No Power to Oven Turn power on
No Power to Oven Check Light circuit – IF OK, Select “Cook” and Check
Timer circuit . IF OK, Check Door Micro Switches
Micro switch not OPENING Check connections & switch functions .
(Caution: the switch components on this control
system pass 115 v . a .c . through switch contacts .)
Fast Control
PROBLEM POSSIBLE CAUSE CORRECTIVE ACTION
Key Pad Buttons Not
Responding
Defective key pad Use key pad diagnostics / pin outs test points
Loose ribbon connection at key pad Check connection
PROBE ERROR in display Faulty Probe Replace probe
Loose probe connection Check connections
HI TEMP In display Oven at too high a temp for product Allow oven to cool
HELP In display Faulty Probe Replace probe
Motor centrifugal switch stuck Check centrifugal switch
Gas valve (s), or Ignition System Check heat generation system – ( Refer to Service
procedures (Heat generation system) - .page
Unit will not shut off Unit above 150°F Put unit into cool down, open door slightly
No HIGH speed But LOW
speed works
Bad key pad Use diagnostic KEY PAD TEST
Bad K2 relay on board Check for voltage out of K2 relay
Bad motor Check motor
No LOW speed But HIGH
speed works
Bad key pad Use diagnostic KEY PAD TEST
Bad K2 relay on board Check for voltage out of K3
Bad motor Check motor
Display is BLANK NO
POWER
Bad transformer Check for 24VAC out of TR1 transformer
Bad harness connection Check connections
Unit will not heat No power out of K4 relay Check for power out of K4 relay
No power out of Ignition Module MV Complete a flame current check to osolate
Gas valve shutoff switch open, PV, MV,
or both valves stuck closed
Check for MV power at gas shutoff switch, and that
PV and MV opens on call for heat
Motor centrifugal not closing Check motor centrifugal switch
Motor stops, then after a
period of time comes back
on
Thermal Trip on motor Inspect rear clearance
Motor air intake is clear of lint/debris
Replace motor